# Oxidation numbers for each element

1. Mar 28, 2009

### chemjem

1. The problem statement, all variables and given/known data

3Ag2 S + 2Al --> 6Ag + Al2 S3
consider the equation for silver tarnishing.
a) state the oxidation number for each element in the reaction.
b)identify the the oxidized reactant and the reduced reactant.

3. The attempt at a solution

Ag2=2 S= -2 Al=0 ---> Ag=-2 Al2=0 S=2

Ag2 loses the electron so it is the oxidized reactant.
S gains the electron so it is the reduced reactant.

am i close to having the right answer?

2. Apr 1, 2009

### chemisttree

Not really. This isn't really a silver tarnishing reaction. It is the opposite of a silver tarnishing reaction. Tarnishing involves the reaction of zero valent metal to its oxidized form.

Yes, the sulfur atom in silver sulfide is at an oxidation state of -2. Literally everything else you have written is incorrect.

Try again. You are on the right track.

3. Apr 1, 2009

### chemjem

thanks for the reply. chemistry is not my thing... i am trying.

4. Apr 2, 2009

5. Apr 2, 2009

### chemjem

Ag2=1 S=0 Al=1 ---> Ag=-1 Al2=-1 S=0

Ag gains the electron so it is reduced
Al loses the electron so it is oxidized

6. Apr 2, 2009

7. Apr 2, 2009

### chemisttree

I'll give you a hint: The sulfur (-2) does not change oxidation state during the reaction. It only swaps partners.

What is the oxidation state of aluminum in the reactant side of the equation (...+ 2Al -->)?